Sintering machine



Aug. 15, 1950 w. M. DUNCAN sm'mamc manna:

4 Sheet s-Sheet 1 Filed June 19, 1947 INVENTOR'.

W1LLIAM M. DUNCAN ATTORNEYS.

Aug. 15, 1950 w. M. DUNCAN 2,519,179

' SINTERING MACHINE Filed June 19, 1947 4 Sheets-Sheet 2 INVENTOR WILLIAM M. DUNCAN ATTORNEYS.

z- 15, 1950 w. DUNCAN 2,519,179

1 SINTERING mcnnm Filed June 19, 1947 4 Sheets-Sheet 3 INVENTOR: WILLIAM M DUNCAN ATTORNEYS.

1950 w. M. DUNCAN 2,519,179

51mm MACHINE Filed June 19, 194'! 4 Slu aets-Sheet 4 FIG. 5. f? l l x i r L SI a2 l l i 58 :1 53 l 4 A -31? l L. l I -&\ &1

i n] 5 gs} 3;

[3 l I I FIG.6

INVENTOR: WILLIAM M. DUNCAN lav/3v a ATTORNEYS.

Patented Aug. 15, 1950 UNITED STATES PATENT OFFICE SINTER ING MACHINE William M. Duncan, Alton, Ill.

Application June 19, 1947, Serial No. 755,770

4 Claims. 1

tially of a series of pallets, each adapted to contain a bed of raw ore. The pallets are arranged to be moved about an endless path, at one extremity of which they are filled and at the other extremity of which they are emptied. While laden with the ore, and the added fuel which is necessary to increase the temperature, the succession of pallets traverses the mouths of a plurality of wind boxes whereby a draft is induced through the bed of material on the pallets.

The sintering machine as described above was originally a reasonably efficient and dependable apparatus for its intended purpose, but with the demand for increased production, more recent efforts to achieve additional capacity, by enlarging the pallets, have reached the point of diminishing return. Of late it has been proposed to construct such sintering machines with pallets having a length (i. e., width of the sintering ma-.

chine) of ten feet or more so that the ore bed on each pallet would weigh many hundred pounds.

With such an apparatus constructed along conventional lines it would be necessary to provide an endless path having a height on the order of fifteen feet with drive sprockets correspondingly proportioned. With a sintering machine of the magnitude just referred to and even with smaller machines, great difliculties are encountered in properly regulating and maintaining the uniformity of the induced draft of air through the ore-fuel bed with resultant lack of uniformity in the sintering of the ore being treated. Furthermore, with pallets of the magnitude referred to, it is practically impossible to control the driving force so as to avoid twists, tortions, and strains, which frequently will result in broken pallets and consequently loss of the ore bed carried thereon. All these factors would contribute toward a marked loss of efliciency and would result in aggravated difliculty in maintenance and in continuity of operations.

The object of the present invention, generally stated, is to provide a sintering apparatus having a high capacitywithout utilizing pallets of such proportions as to be impractical.

Another object of the invention is to provide expeditiously removed and replaced in their operative succession without interrupting'the continuous operation of the machine.

A further object is to provide an improved drive for the pallets of the sintering machine, which will assure the movement of the pallets along their track without twisting and skewing.

Other objects will become apparent as the following description is read in connection with the accompanying drawings in which:

Figure 1 is a view in side elevation of a sintering machine constructed in accordance with the present invention;

Figure 2 is a sectional view taken along line 2-2 of Figure 1;

Figure 3 is an enlarged detail view of the drive sprocket for the sintering ma, neishown. in

ure 1;

Figure 4 is a sectional view taken along line 4-1 of Figure 3;

Figure 5 is a sectional view showing in plan a pallet transfer mechanism constructed in accordance with the present invention;

Figure 6 is a view in side elevation of the pallet transfer mechanism; and

Figure '7 is a sectional view taken along line 1--'| of Figure 6.

For economy of floor space, freedom from mechanical difliculties and assurance of uniform sintering of the ore bed, together with relatively high capacity, the present invention contemplates, in general, that a sintering machine be provided with a plurality of strands of pallets so disposed with reference to each other as to operate in parallel, and otherwise so coordinated that the attention of one operative crew will s'uffice. A particular feature of the present invention resides in the arrangement of the wind boxes for the respective strands of pallets so as to be individually controlled yet energizable by a common source and utilizing a single dust collector.

A further feature of the invention resides in the provision of a drive and interlocking connections with the several pallets of a character such that radial displacement between the opposite ends of the pallets due to torsional twist of the driver shaft or due to wear of the interlocking connections is substantially prevented.

Referring now to Figures 1 and 2 of the drawings, a succession of pallets l is mounted upon a stationary endless track having an upper reach 2, which is substantially horizontal, and an inclined lower reach 3. The present invention contemplates that the pallets I be preferably not over a sintering machine wherein the pellets may be feet long and not over twenty-four inches wide. The pallets l are otherwise constructed in accordance with the usual practice having a grated bottom.

At the end portions, the endless track is preferably in the form of a channel, as shown clearly in Figure 4, so that flanges 4 and 5 lie respectively on the radially outward and radially inward sides of trunnions 6 which extend from each end of each pallet. The reaches 2 and 3, which intervene the end portions of the endless track,

need not be provided with fiangesboth above and below the trunnions 6, it being sufficient, and in fact preferred, that along the reaches 2 and 3, the flanges of the track extend only beneath the trunnions 6.

In accordance with the usual practice, the trunnions 6 may be provided with rollers.

As in any such sintering machine, a feed bin 1 is mounted above the endless track for the pallets near one end thereof and is provided with a swinging spout 8 (of the conventional type) and a suitable control valve 9. As shown in Figure 2, where the sintering machine of the present invention consists of two separate strands of pallets, duplicate such feed bins and spouts are provided.

Adjacent the feed bin 1 a suitable ignition furnace I is provided for igniting the mixture of ore and fuel with which the respective pallets are laden.

Arranged below the upperreach of the track 2 and extending from a position directl beneath the ignition furnace l0 toward the dis arge end of the machine is a plurality of wind boxes ll, each arranged in accordance with the usual practice to extend as close as practicable to the bottoms of the several pallets l as the latter traverse their endless path. The wind boxes I for the left hand strand of pallets (as seen in Figur 2) are duplicated by corresponding series of wind boxes l2 arranged for the right strand of pallets (as seen in Figure 2).

In order to conserve space and at the same time contribute toward the efliciency of dust separation from the gases exhausted through wind boxes H and I2, the present invention contemplates that the ducts connecting wind boxes H and I2 for'the respective pallet strand be in the form of a Y. The branches l3 and ll of the Y duct connect respectively with the wind boxes II and I2 and merge into a constricted vertical leg l which extends downwardly, between the two strands of pallets, and constitutes a unitary duct leading to a single dust collector |6 adapted to receive the output of both wind boxes II and l2. The arrangement just described has the further feature of accommodating the pallet transfer mechanism later to be described. In order to regulate the draft induced through the ore beds above the wind boxes II and I2, respectively, the branches l3 and II are each provided with suitable dampers I30 and H0. In this way ore beds differing in composition and/or characteristics maybe concurrently treated on the respective strands.

As shown by the drawings, the dust collector I6 is energized by two vacuum systems "and I8, but it should be understood that one exhauster of appropriate capacity will suffice. The merging to ether of the dust laden gaseous output of 'wind boxes H and I2 and the constriction of the interflowed streams from such wind boxes respectively contributes toward the emciency of dust recovery.

For driving the series of pallets about their 'the sintering machine.

endless path a pair of sprockets 20 is provided for the left strand (as seen in Figure 2) and a corresponding pair of sprockets 2| for the right strand. The paired sprockets are mounted upon shafts 22 and 23 respectively suitably supported in appropriate bearings upon the framework of Mounted centrally upon each of the shafts 22 and 23 is a drive gear 24 which engages a pinion 25 mounted upon a jack shaft 28. The jack shaft 26 is driven by a motor 21. While in the embodiment shown in the drawings the jack shaft 26 transmits the power from motor 2'! to the driving gears 24 for both pairs of sprockets, it will be understood that, if desired, separate motor drives for each strand may be provided. Any suitable .clutch for selectively engaging or disengaging the driving connection between motor 21 and shafts 22 or 23 is preferably provided. Such a clutch may, for example, involve mounting the gears 24 upon a spline so as to be slidable axially of their shafts 22 and 23, respectively, into positions whereat they will either engage with or be disengaged from the pinions 25. Alternatively, the clutch may involve a similar shift of the axial position of the pinions 25. Likewise, it is desirable to provide variable speed transmissions between the drive shaft and the driving pinions, thereby to control the lineal speed of one strand of pallets independently of the other where it is desirable to do so. Since clutch mechanisms and variable speed transmissions of the character required are well known in the art, the details thereof are not shown in the accompanying drawings.

The disposition of the drive gear 24 midway between the sprockets 20 or 2|, as shown in the drawings, is of particular advantage in that any torsional twist to which the shaft 22 may be subject, because of the tangential load which is imposed on the sprockets, is equally distributed on both sides of the drive gear 24. Consequently, if such torsional twist should attain a magnitude such that either of the sprockets 20 lags behind its normal unstrained position relative to gear 24, both sprockets will lag to the same degree. Such an arrangement therefore eliminates the troublesome cooking of the pallets on their track, which has heretofore been experienced with drives which were powered from one end only.

In order to further reduce the tendency of the pallets to cock in their track and to facilitate the movement of the pallets about the turns in the endless track, the present invention contemplates that each of the sprockets be provided with roller teeth in lieu of the usual integral teeth. Consequently, in the embodiment shown, the sprockets 20 and 2| are provided about their periphery with a. series of rollers 28 mounted upon shafts 28, which latter are supported between spaced legs 30 preferably cast integral with the sprocket 20, in the radial positions of the usual sprocket teeth. The rollers 28 are circumferentially spaced to correspond with the spacing of trunnions 6 on each of the pallets, which is to say that the inter-axial spacing between two successive rollers 28 is the same as the inter-axial spacing between two successive trunnions 6, whether the latter are on the same or difierent pallets. It is preferable, however, that the rollers 28 be selected of a diameter slightly less than the linear distance between the proximate peripheries of succeeding trunnions '6. Otherwise, when there is rolling movement between a iven roller 28 and a trunnion 6 immediately ahead of it, there might be sliding movement between said roller and the trunnion engaging the same on the other side.

At the discharge end of the sintering machine. a curved track 3| is provided for directing the pallets from the upper reach 2 to the lower reach 3 In order to facilitate the removal and replacement of pallets having burned out grate bars, without interrupting the operation of the sintering machine, the present invention contemplates the provision of a lift and transfer mechanism between the upper and lower reaches of the endless path for the pallets. The arrangement of the lift and transfer mechanism in this manner is made possible by the novel arrangement of the wind boxes and ducts as described above. In the space which, in accordance with the prior practice, has been occupied by the ducts leading from the wind boxes the present invention contemplates the provision of an over-head rail or trolley 32, which is mounted so as to extend substantially horizontally between the upper and lower reaches of the pallet series. For a substantial distance between the upper and lower reaches of the pallet series, the trolley 32 extends in a direction parallel to the length of the sintering machine, but toward the drive sprockets the trolley curves, as shown clearly in Figure 5, so as to extend to the exterior of the sintering machine.

Mounted upon the trolley 32 is a pair of dual hoists 33 a d 34. The hoists33 and 34 may be identical and each is preferably provided with two lifting mechanisms interlocked so as to operate together. For example, in the embodiment 1 shown, the mechanisms are compressed-air-operated and the hoist 33 is pro id d with two air cylinders 35 and 36, one on each side of the trolley 32. Likewise, the hoist 34 is provided with two air cylinders 31 and 38, one on each side of the trolley 32. Cylinders 3'3 and 3: wor" together but entirely separate from cylinders 31 and 38, which latter work together.

In the embodiment shown, the two pairs of dual hoists are inter-connected to provide a unitary transfer mechanism, which is mounted upon wheels 39 entracked upon trolley 32.

With such an apparatus the removal and replacement of a pallet from the series may be accomplished with facility and speed. From outwardly beyondthe confines of the sintering machine, the transfer meohanism may be moved with hoist 34 laden with a new pallet 45! suspended upside-down ready to. be dropped into position in the series of pallets when one is removed. When the transfer mechanism is moved to the interior of the slntering machine, bearing a new pallet 40 as just described, it is contemplated that the hoist 33 be unloaded. When the pallet which it is desired to remove from the machine reaches a position beneath the hoist 33, said pallet is engaged by the hoist, lifted out of position in the series, and then, while the removed pallet is still suspended by hoist 33, hoist 34 is lowered to deposit pallet 40 in position in the series.

Between the operation of the two hoists 33 and 34, as just described, sufficient time may elapse that one or more pallets have passed the locus of operation so that the new pallet may not be in the exact position relative to the other pallets as was the removed pallet, but s ch is immaterial.

In order to retard the mo ement of the succession of pallets past the locus at which the interchange just described is being made, the invention further contemplates the provision of a brake 4| having a shoe 42 adapted to frictionally engage the bottom surface of the pallets as they traverse a position immediately in advance of the locus at which the interchange is being made. The brake 4i is not a positive brake, which would require interruption of the machine, but is preferably an impositive brake which, while retarding the movement of pallets along the lower reach of the machine, will, none the less, permit the machine to continue in operation. In t e embodiment shown in the drawings, the brake 4| is provided with a spring 43 tending to hold shoe 42 in engagement with the pallets. The spring 43 operates through a lever 44 secured as a crank upon a shaft 45. The shaft 45 is also provided with a gear 46 driven by a pinion 41 from a crank 48 so as to facilitate the movement of lever 44 from the position shown in Figure 6 to an opposite position whereat the tension of spring 43 will tend to rotate lever 44 in the opposite sense. Upon the extremity of shaft 45, an eccentri" 49 is provided and upon said eccentric the brake shoe 42 is carried. With such an organization of parts, it is apparent that, when the parts are in the position shown in Figure 6, the spring 43 tends to move the shoe 42 so as to grip and retard the movement of the pallets, but, undcr normal operating conditions, the par s will assume a position wherein lever 44 extends in a nearly opposie direction to that shown in the drawings. In the latter position the tension of spring 43 will tend to maintain the shoe 4'2 out of engagement with the rallets. While the brake 4 is prima-rily intended for retarding the movement of the pallets along the inclined lower reach o their path during interchange, such a brake ma n ne the less be continuously employed, and in fact a plurality thereof may *e provided along te ower reach of the pallet path, so as to re ard the movement of the pallets thereo especially when the path may be incom'letely filled with pallets.

With the transfer mechanism of the haracter 45 above described, a replacement rallet may be moved into position and the pallet, bun; replaced, taken from the sintering machine and deposited beyond the confines thereof with but one maneuver of the transfr mechanism along its 50 track 32. it being understood that, somewhere in a convenient location beyond the confines o" the sintering machine, there will exist 2. apply of r placement pallets and a point for disposing of the pallets to be reconditioned, both of which will be served by trolley 32.

In order that the hoists 33 and 34 may readily engage the pallets, the hoists are provided with a set of toggle hooks 53 and 54, the upper ends of which are pivoted on a collar 55, which is slidably mounted on the rod extending from the piston within each of cylinders 35--36 and 31-38, as the case may be. The lower end of the piston rod is secured to a head 55. A pair of links 51 extend between head 56 and toggle hooks 54. The

toggle hooks 54 have their lower extremities proportioned to pass between the bars which constitute the grated bottom of the several pallets and engaged projections therein located, it being understood that during the transfer operation the pallets are upside-down.

A further feature of the present invention involves the provision of a hood 5!! adjacent the discharge end of the sintering machine and embracing the last wind box of the series II as well as a negative wind box M. The terminal wind box Bl may be identical in structure with the other wind boxes of the series H. Save that the flow of gas through the box is opposite in direction to the flow of air through the series ll, wind box 5| is preferably provided with a suitable blower for drawing cool air from the atmosphere and forcing the same upwardly through wind box 5|. Flue gas flows downwardly through boxes I I while cool air flows upwardly through box 5|. Consequently, the flow of air through the pallets above wind box 5| is in an upward direction as distinguished from the down flow of air through the palletsv above the wind boxes ll. Such a reversal of the flow of air through the ore bed on the pallets for a brief interval contributes to the efllciency of the sintering operation particularly as concerns particles of fuel or ore which may have been baflled (due to their peculiar disposition in the bed) against air flowing in the opposite direction. Hood 50 directs the air (which has been preheated by passing upwardly through the pallets above windbox 5|) into the last wind box of the series I I, thus facilitating combustion of the last vestige of fuel remaining in the bed. Moreover, such reversal of the flow of air through the sinter bed has an important cooling effect upon the hottest part of the sinter, which is deep in the bed, thus sufficiently hardening the semi-plastic sinter that it will slide freely from the grate bars.

From the foregoing description, those skilled in the art should readily understand that the invention accomplishes its objects and that, by the provision of a plural strand sintering machine, numerous mechanical and operational advantages are attainable. While the various features of the machine have been described with particular reference to plural strand sintering machines,

it should be understood that many of such features are applicable to single strand machines and it is therefore to be distinctly understood that certain aspects of the invention are not limited to plural strand sintering machines.

While one complete embodiment has been disclosed in detail, various modifications and alterations will immediately suggest themselves to those skilled in the art and it is therefore to be distinctly understood that such modifications and variations as do not depart from the spirit of the invention are, although not specifically described herein, contemplated by and within the scope of the appended claims.

Having thus described the invention, what is claimed and desired to be secured by Letters Patent is:

1. In an apparatus for sintering ores, a plurality of series of pallets mounted on endless tracks, each series having separate parallel closely adjacent tracks, separate wind boxes below the upper reaches of each of said tracks respectively, exhaust means adapted to pull air through pallets disposed above the wind boxes respectively, a dust collector, and a unitary duct connected to both lector.

2. In an apparatus for sintering ores, a plurality of series of pallets mounted on endless tracks, each series having separate parallel closely adjacent tracks, separate wind boxes below the upper reaches of each of said tracks respectively, exhaust means adapted to pull air through pallets disposed above the wind boxes respectively, a dust collector, and a Y-duct extending from said separate wind boxes to said dust collector, the leg of said Y-duct extending vertically between the respective wind boxes.

3. In an apparatus for sintering ores, a plurality of series of pallets mounted on endless tracks, each series having separate parallel closely adjacent tracks, separate wind boxes below the upper reaches of each of said tracks respectively, exhaust means adapted to pull air through pallets disposed above the wind boxes respectively, a dust collector, a unitary duct connected to both said wind boxes and extending to said dust collector, each of said series having one wind box free of direct connection with said dust collector, and a hood overlying said last mentioned wind box and the next adjacent wind box for substantially limiting the air drawn through said next adjacent wind box to air which has been preheated by having first traversed pallets above said one wind box, said one wind box being positioned under said hood at the side toward the discharge end of said endless track.

4. In an apparatus for sintering ores having a series of pallets mounted for movement about an endless track; a succession of wind boxes opening in close adjacence to and beneath the series of pallets, means for drawing air downwardly through said wind boxes, a final similarly disposed wind box unconnected with said means but vented to the atmosphere below the pallets, and a hood embracing the pallets above said final wind box and the next adjacent wind box to limit the flow of air through the pallets above said adjacent wind box to that which has been preheated by passing upwardly through the pallets above said final wind box.

WILLIAM M. DUNCAN.

REFERENCES CITED Thefollowing references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,618,205 Knox Feb. 22, 1927 1,724,700 Ermold Aug. 13, 1929 1,800,571 Shallock et a1. Apr. 14, 1931 1,904,720 Douglass Apr. 18, 1933 2,143,905 Ahlmann Jan. 17, 1939 2,148,052' Ahlmann Feb. 21, 1939 2,247,787 Schmidt July 1, 1941 2,304,381 Shallock Dec. 8, 1942 2,386,393 Gelblnan Oct. 9, 1945 2,441,383 Babb May 11, 1948 

